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Amazon Route 53
Developer Guide (API Version 2013-04-01)

Values for Weighted Records

When you create weighted records, you specify the following values.

Name

Enter the name of the domain or subdomain that you want to route traffic for. The default value is the name of the hosted zone.

Note

If you're creating a record that has the same name as the hosted zone, don't enter a value (for example, an @ symbol) in the Name field.

Enter the same name for all of the records in the group of weighted records.

CNAME records

If you're creating a record that has a value of CNAME for Type, the name of the record can't be the same as the name of the hosted zone.

Special characters

For information about how to specify characters other than a-z, 0-9, and - (hyphen) and how to specify internationalized domain names, see DNS Domain Name Format.

Wildcard characters

You can use an asterisk (*) character in the name. DNS treats the * character either as a wildcard or as the * character (ASCII 42), depending on where it appears in the name. For more information, see Using an Asterisk (*) in the Names of Hosted Zones and Records.

Type

The DNS record type. For more information, see Supported DNS Record Types.

Select the same value for all of the records in the group of weighted records.

Alias

Select No.

TTL (Time to Live)

The amount of time, in seconds, that you want DNS recursive resolvers to cache information about this record. If you specify a longer value (for example, 172800 seconds, or two days), you pay less for Route 53 service because recursive resolvers send requests to Route 53 less often. However, it takes longer for changes to the record (for example, a new IP address) to take effect because recursive resolvers use the values in their cache for longer periods instead of asking Route 53 for the latest information.

If you're associating this record with a health check, we recommend that you specify a TTL of 60 seconds or less so clients respond quickly to changes in health status.

You must specify the same value for TTL for all of the records in this group of weighted records.

Note

If you create two or more weighted records that have the same name and type, and you specify different values for TTL, Route 53 changes the value of TTL for all of the records to the last value that you specified.

If a group of weighted records includes one or more weighted alias records that are routing traffic to an ELB load balancer, we recommend that you specify a TTL of 60 seconds for all of the non-alias weighted records that have the same name and type. Values other than 60 seconds (the TTL for load balancers) will change the effect of the values that you specify for Weight.

Value

Enter a value that is appropriate for the value of Type. For all types except CNAME, you can enter more than one value. Enter each value on a separate line.

A — IPv4 address

An IP address in IPv4 format, for example, 192.0.2.235.

AAAA — IPv6 address

An IP address in IPv6 format, for example, 2001:0db8:85a3:0:0:8a2e:0370:7334.

CAA — Certificate Authority Authorization

Three space-separated values that control which certificate authorities are allowed to issue certificates or wildcard certificates for the domain or subdomain that is specified by Name. You can use CAA records to specify the following:

  • Which certificate authorities (CAs) can issue SSL/TLS certificates, if any

  • The email address or URL to contact when a CA issues a certificate for the domain or subdomain

CNAME — Canonical name

The fully qualified domain name (for example, www.example.com) that you want Route 53 to return in response to DNS queries for this record. A trailing dot is optional; Route 53 assumes that the domain name is fully qualified. This means that Route 53 treats www.example.com (without a trailing dot) and www.example.com. (with a trailing dot) as identical.

MX — Mail exchange

A priority and a domain name that specifies a mail server, for example, 10 mailserver.example.com.

NAPTR — Name Authority Pointer

Six space-separated settings that are used by Dynamic Delegation Discovery System (DDDS) applications to convert one value to another or to replace one value with another. For more information, see NAPTR Record Type.

PTR — Pointer

The domain name that you want Route 53 to return.

SPF — Sender Policy Framework

An SPF record enclosed in quotation marks, for example, "v=spf1 ip4:192.168.0.1/16-all". SPF records are not recommended. For more information, see Supported DNS Record Types.

SRV — Service locator

An SRV record. For information about SRV record format, refer to the applicable documentation. The format of an SRV record is:

[priority] [weight] [port] [server host name]

For example:

1 10 5269 xmpp-server.example.com.

TXT — Text

A text record. Enclose text in quotation marks, for example, "Sample Text Entry".

Routing Policy

Select Weighted.

Weight

A value that determines the proportion of DNS queries that Route 53 responds to using the current record. Route 53 calculates the sum of the weights for the records that have the same combination of DNS name and type. Route 53 then responds to queries based on the ratio of a resource's weight to the total.

You can't create non-weighted records that have the same values for Name and Type as weighted records.

Enter an integer between 0 and 255. To disable routing to a resource, set Weight to 0. If you set Weight to 0 for all of the records in the group, traffic is routed to all resources with equal probability. This ensures that you don't accidentally disable routing for a group of weighted records.

The effect of setting Weight to 0 is different when you associate health checks with weighted records. For more information, see How Amazon Route 53 Chooses Records When Health Checking Is Configured.

Set ID

Enter a value that uniquely identifies this record in the group of weighted records.

Associate with Health Check/Health Check to Associate

Select Yes if you want Route 53 to check the health of a specified endpoint and to respond to DNS queries using this record only when the endpoint is healthy. Then select the health check that you want Route 53 to perform for this record.

Route 53 doesn't check the health of the endpoint specified in the record, for example, the endpoint specified by the IP address in the Value field. When you select a health check for a record, Route 53 checks the health of the endpoint that you specified in the health check. For information about how Route 53 determines whether an endpoint is healthy, see How Amazon Route 53 Determines Whether a Health Check Is Healthy.

Associating a health check with a record is useful only when Route 53 is choosing between two or more records to respond to a DNS query, and you want Route 53 to base the choice in part on the status of a health check. Use health checks only in the following configurations:

  • You're checking the health of all of the records in a group of failover, geolocation, latency, multivalue, or weighted records, and you specify health check IDs for all the records. If the health check for a record specifies an endpoint that is not healthy, Route 53 stops responding to queries using the value for that record.

  • You select Yes for Evaluate Target Health for an alias record or the records in a group of failover alias, geolocation alias, latency alias, or weighted alias record. If the alias records reference non-alias records in the same hosted zone, you must also specify health checks for the referenced records.

For geolocation records, if an endpoint is unhealthy, Route 53 looks for a record for the larger, associated geographic region. For example, suppose you have records for a state in the United States, for the United States, for North America, and for all locations (Location is Default). If the endpoint for the state record is unhealthy, Route 53 checks the records for the United States, for North America, and for all locations, in that order, until it finds a record that has a healthy endpoint.

If your health checks specify the endpoint only by domain name, we recommend that you create a separate health check for each endpoint. For example, create a health check for each HTTP server that is serving content for www.example.com. For the value of Domain Name, specify the domain name of the server (such as us-east-2-www.example.com), not the name of the records (example.com).

Important

In this configuration, if you create a health check for which the value of Domain Name matches the name of the records and then associate the health check with those records, health check results will be unpredictable.